As a fond mother, when the day is o'er, Leads by the hand her little child to bed, Half willing, half reluctant to be led, And leave his broken playthings on the floor. Still gazing at them through the open door, Nor wholly reassured and comforted By promises of others in their stead Which, the more splendid, may not please him more; So Nature deals with us, and takes away Our playthings one by one, and by the hand Leads us to rest so gently, that we go Scarce knowing if we wish to go or stay, Being too full of sleep to understand How far the unknown transcends the what we know.

Tyndall declared that he saw in Matter the promise and potency of all forms of life, and with his Irish graphic lucidity made a picture of a world of magnetic atoms, each atom with a positive and a negative pole, arranging itself by attraction and repulsion in orderly crystalline structure. Such a picture is dangerously fascinating to thinkers oppressed by the bloody disorders of the living world. Craving for purer subjects of thought, they find in the contemplation of crystals and magnets a happiness more dramatic and less childish than the happiness found by mathematicians in abstract numbers, because they see in the crystals beauty and movement without the corrupting appetites of fleshly vitality.